Systems and methods for cleaning an endoscopic instrument

ABSTRACT

A method comprises, based on a position of a medical instrument within a patient anatomy, determining, by a control system, whether an obstruction is on a surface of a lens of the medical instrument. The method further comprises, based on a determination that the obstruction is on the surface of the lens, instructing, by the control system, a valve control mechanism to open a valve to release a flow of pressurized fluid through a nozzle of the medical instrument and over the surface of the lens. The valve is configured to control provision of the pressurized fluid.

RELATED APPLICATIONS

This patent application claims priority to and the benefit of the filingdate of U.S. Provisional Patent Application 62/037,299, entitled“SYSTEMS AND METHODS FOR CLEANING AN ENDOSCOPIC INSTRUMENT,” filed Aug.14, 2014, which is incorporated by reference herein in its entirety.

FIELD

The present disclosure is directed to systems and methods for cleaning,and more particularly, to systems and methods for cleaning an endoscopicinstrument while inside of a patient.

BACKGROUND

Minimally invasive medical techniques are intended to reduce the amountof tissue that is damaged during medical procedures, thereby reducingpatient recovery time, discomfort, and harmful side effects. Suchminimally invasive techniques may be performed through natural orificesin a patient anatomy or through one or more surgical incisions.Clinicians may insert medical tools through these natural orifices orincisions to reach a target tissue location. Medical tools includeinstruments such as therapeutic instruments, diagnostic instruments, andsurgical instruments. To reach the target tissue location, a minimallyinvasive medical tool may navigate natural or surgically createdpassageways in anatomical systems such as the lungs, the colon, theintestines, the kidneys, the heart, the circulatory system, or the like.

Minimally invasive medical procedures may rely upon visualizationsystems to find a target location and perform various operations.Particularly, a visualization system may help a minimally invasivemedical instrument navigate natural or surgically created passageways inanatomical systems to reach the target tissue location. For example, thevisualization system may help guide the minimally invasive medicalinstrument through natural passageways in the lungs, the colon, theintestines, the kidneys, the heart, the circulatory system, or the like.Some minimally invasive medical instruments may be teleoperated orotherwise computer-assisted.

During navigation of the medical instrument, or during an operationperformed by the medical instrument, the lens of the visualizationsystem may become obstructed or clouded by patient tissue or fluids.Such obstructions can make navigation or operation more difficult. Thus,it is desirable to clean the lens of the visualization system in amanner that is safe for the patient.

SUMMARY

The embodiments of the invention are summarized by the claims thatfollow below.

In one embodiment, a method includes providing a medical instrument,initiating a flow of a pressurized fluid across a surface of the medicalinstrument, the pressurized fluid having a pressure that is greater thana standard operating room supply, and terminating the flow of thepressurized fluid after a predetermined duration.

In another embodiment, a method includes providing a pressurized fluidwith a pressure augmenting mechanism and passing a flow of thepressurized fluid across a surface of a medical instrument. The pulse ofpressurized fluid extends for a predetermined duration.

In another embodiment, a system includes a medical instrument, a nozzle,a pressure augmenting mechanism connected to the nozzle, a valve betweenthe pressure augmenting mechanism and the nozzle, and a valve controlmechanism configured to control the valve to release a flow ofpressurized fluid, for a predetermined duration, from the pressurizedaugmenting mechanism through the nozzle and over a surface of themedical instrument.

BRIEF DESCRIPTIONS OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale. In fact, thedimensions of the various features may be arbitrarily increased orreduced for clarity of discussion. In addition, the present disclosuremay repeat reference numerals and/or letters in the various examples.This repetition is for the purpose of simplicity and clarity and doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed.

FIG. 1 is a diagram showing an illustrative teleoperational medicalsystem, according to one example of principles described herein.

FIG. 2 is a diagram showing an illustrative medical instrument systemcomprising an endoscopic visualization system, according to one exampleof principles described herein.

FIG. 3 is a front view of the front of an endoscopic visualizationsystem, according to one example of principles described herein.

FIG. 4 is a diagram showing an illustrative system to providepressurized fluid to the lens of an endoscopic visualization system,according to one example of principles described herein.

FIG. 5A is a front view of a nozzle for providing fluid to a surface ofa lens of an endoscopic visualization system, according to one exampleof principles described herein.

FIG. 5B is a cross-sectional view of a nozzle for providing fluid to asurface of a lens of an endoscopic visualization system, according toone example of principles described herein.

FIG. 6 is a perspective view of a rounded slot nozzle for providingfluid to a surface of a lens of an endoscopic visualization system,according to one example of principles described herein.

FIG. 7 is a graph showing a pulse signal to cause a pulse of fluid to beapplied to a lens of an endoscopic visualization system, according toone example of principles described herein.

FIGS. 8A and 8B are diagrams illustrating obstructions on the surface ofa lens, according to one example of principles described herein.

FIG. 9 is a flowchart showing an illustrative method for clearing thelens of an endoscopic visualization system, according to one example ofprinciples described herein.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the disclosure is intended. In the following detaileddescription of the aspects of the invention, numerous specific detailsare set forth in order to provide a thorough understanding of thedisclosed embodiments. However, it will be obvious to one skilled in theart that the embodiments of this disclosure may be practiced withoutthese specific details. In other instances well known methods,procedures, components, and circuits have not been described in detailso as not to unnecessarily obscure aspects of the embodiments of theinvention.

Any alterations and further modifications to the described devices,instruments, methods, and any further application of the principles ofthe present disclosure are fully contemplated as would normally occur toone skilled in the art to which the disclosure relates. In particular,it is fully contemplated that the features, components, and/or stepsdescribed with respect to one embodiment may be combined with thefeatures, components, and/or steps described with respect to otherembodiments of the present disclosure. In addition, dimensions providedherein are for specific examples and it is contemplated that differentsizes, dimensions, and/or ratios may be utilized to implement theconcepts of the present disclosure. To avoid needless descriptiverepetition, one or more components or actions described in accordancewith one illustrative embodiment can be used or omitted as applicablefrom other illustrative embodiments. For the sake of brevity, thenumerous iterations of these combinations will not be describedseparately. For simplicity, in some instances the same reference numbersare used throughout the drawings to refer to the same or like parts.

The embodiments below will describe various instruments and portions ofinstruments in terms of their state in three-dimensional space. As usedherein, the term “position” refers to the location of an object or aportion of an object in a three-dimensional space (e.g., three degreesof translational freedom along Cartesian X, Y, Z coordinates). As usedherein, the term “orientation” refers to the rotational placement of anobject or a portion of an object (three degrees of rotationalfreedom—e.g., roll, pitch, and yaw). As used herein, the term “pose”refers to the position of an object or a portion of an object in atleast one degree of translational freedom and to the orientation of thatobject or portion of the object in at least one degree of rotationalfreedom (up to six total degrees of freedom). As used herein, the term“shape” refers to a set of poses, positions, or orientations measuredalong an object.

According to various embodiments, medical procedures, such as biopsyprocedures, may be performed using a teleoperational system to guideinstrument delivery. Referring to FIG. 1 of the drawings, ateleoperational medical system for use in, for example, medicalprocedures including diagnostic, therapeutic, or surgical procedures, isgenerally indicated by the reference numeral 100. As will be described,the teleoperational medical systems of this disclosure are under theteleoperational control of a surgeon. In alternative embodiments, ateleoperational medical system may be under the partial control of acomputer programmed to perform the procedure or sub-procedure. In stillother alternative embodiments, a fully automated medical system, underthe full control of a computer programmed to perform the procedure orsub-procedure, may be used to perform procedures or sub-procedures. Asshown in FIG. 1, the teleoperational medical system 100 generallyincludes a teleoperational assembly 102 mounted to or near an operatingtable O on which a patient P is positioned. A medical instrument system104 is operably coupled to the teleoperational assembly 102. An operatorinput system 106 allows a surgeon or other type of clinician S to viewimages of or representing the surgical site and to control the operationof the medical instrument system 104. The operator input system 106 maybe referred to as a master or surgeon's console.

The operator input system 106 may be located at a surgeon's console,which is usually located in the same room as operating table O. Itshould be understood, however, that the surgeon S can be located in adifferent room or a completely different building from the patient P.Operator input system 106 generally includes one or more controldevice(s) for controlling the medical instrument system 104. Morespecifically, in response to the surgeon's input commands, the controlsystem 112 effects servomechanical movement of medical instrument system104. The control device(s) may include one or more of any number of avariety of input devices, such as hand grips, joysticks, trackballs,data gloves, trigger-guns, hand-operated controllers, voice recognitiondevices, touch screens, body motion or presence sensors, and the like.In some embodiments, the control device(s) will be provided with thesame degrees of freedom as the medical instruments of theteleoperational assembly to provide the surgeon with telepresence, theperception that the control device(s) are integral with the instrumentsso that the surgeon has a strong sense of directly controllinginstruments as if present at the surgical site. In other embodiments,the control device(s) may have more or fewer degrees of freedom than theassociated medical instruments and still provide the surgeon withtelepresence. In some embodiments, the control device(s) are manualinput devices which move with six degrees of freedom, and which may alsoinclude an actuatable handle for actuating instruments (for example, forclosing grasping jaws, applying an electrical potential to an electrode,delivering a medicinal treatment, and the like).

The teleoperational assembly 102 supports the medical instrument system104 and may include a kinematic structure of one or more non-servocontrolled links (e.g., one or more links that may be manuallypositioned and locked in place, generally referred to as a set-upstructure) and a teleoperational manipulator. The teleoperationalassembly 102 includes plurality of motors that drive inputs on themedical instrument system 104. These motors move in response to commandsfrom the control system (e.g., control system 112). The motors includedrive systems which when coupled to the medical instrument system 104may advance the medical instrument into a naturally or surgicallycreated anatomical orifice. Other motorized drive systems may move thedistal end of the medical instrument in multiple degrees of freedom,which may include three degrees of linear motion (e.g., linear motionalong the X, Y, Z Cartesian axes) and in three degrees of rotationalmotion (e.g., rotation about the X, Y, Z Cartesian axes). Additionally,the motors can be used to actuate an articulable end effector of theinstrument for grasping tissue in the jaws of a biopsy device or thelike.

The teleoperational medical system 100 also includes an image capturesystem 108 with one or more sub-systems for capturing images from thesurgical workspace at the distal end of the medical instrument system104. The system operator sees images, captured by an image capturesystem 108, presented for viewing on a display system 110 operativelycoupled to or incorporated into the operator input system 106. Thedisplay system 110 displays an image or representation of the surgicalsite and medical instrument system(s) 104 as generated by sub-systems ofthe image capture system 108. The display system 110 and the operatorinput system 106 may be oriented so the operator can control the medicalinstrument system 104 and the operator input system 106 with theperception of telepresence. The display system 110 may include multipledisplays such as separate right and left displays for presentingseparate images to each eye of the operator, thus allowing the operatorto view stereo images.

The teleoperational medical system 100 also includes a fluid managementsystem 109 for delivering or evacuating fluid through the medicalinstrument system 104. For example, the fluid management system 109 mayinclude a fluid delivery system for delivering air, carbon dioxide, orsaline through the instrument to clean the distal end of the instrument.The fluid management system may also include a suction system to removefluid and debris from the patient internal surgical workspace.

Alternatively or additionally, display system 110 may present images ofthe surgical site recorded and/or imaged preoperatively orintra-operatively using imaging technology such as computerizedtomography (CT), magnetic resonance imaging (MRI), fluoroscopy,thermography, ultrasound, optical coherence tomography (OCT), thermalimaging, impedance imaging, laser imaging, nanotube X-ray imaging, andthe like. The presented preoperative or intra-operative images mayinclude two-dimensional, three-dimensional, or four-dimensional(including e.g., time based or velocity based information) images andassociated image data sets for reproducing the images.

The teleoperational medical system 100 also includes a control system112. The control system 112 includes at least one memory and at leastone processor (not shown), and typically a plurality of processors, foreffecting control between the medical instrument system 104, theoperator input system 106, the image capture system 108, and the displaysystem 110. The control system 112 also includes programmed instructions(e.g., a computer-readable medium storing the instructions) to implementsome or all of the methods described in accordance with aspectsdisclosed herein. While control system 112 is shown as a single block inthe simplified schematic of FIG. 1, the system may include two or moredata processing circuits with one portion of the processing optionallybeing performed on or adjacent the teleoperational assembly 102, anotherportion of the processing being performed at the operator input system106, and the like. Any of a wide variety of centralized or distributeddata processing architectures may be employed. Similarly, the programmedinstructions may be implemented as a number of separate programs orsubroutines, or they may be integrated into a number of other aspects ofthe teleoperational systems described herein. In one embodiment, controlsystem 112 supports wireless communication protocols such as Bluetooth,IrDA, HomeRF, IEEE 802.11, DECT, and Wireless Telemetry.

In some embodiments, control system 112 may include one or more servocontrollers that receive force and/or torque feedback from the medicalinstrument system 104. Responsive to the feedback, the servo controllerstransmit signals to the operator input system 106. The servocontroller(s) may also transmit signals instructing teleoperationalassembly 102 to move the medical instrument system(s) 104 which extendinto an internal surgical site within the patient body via openings inthe body. Any suitable conventional or specialized servo controller maybe used. A servo controller may be separate from, or integrated with,teleoperational assembly 102. In some embodiments, the servo controllerand teleoperational assembly are provided as part of a teleoperationalarm cart positioned adjacent to the patient's body.

The teleoperational medical system 100 may further include optionaloperation and support systems (not shown) such as illumination systems,steering control systems, irrigation systems, and/or suction systems. Inalternative embodiments, the teleoperational system may include morethan one teleoperational assembly and/or more than one operator inputsystem. The exact number of manipulator assemblies will depend on thesurgical procedure and the space constraints within the operating room,among other factors. The operator input systems may be collocated orthey may be positioned in separate locations. Multiple operator inputsystems allow more than one operator to control one or more manipulatorassemblies in various combinations.

FIG. 2 illustrates a medical instrument system 200, which may be used asthe medical instrument system 104 of teleoperational medical system 100for insertion into a patient's body at either a natural orifice or asurgically created orifice. Alternatively, the medical instrument system200 may be used for non-teleoperational exploratory procedures or inprocedures involving traditional manually operated medical instruments,such as endoscopy.

The instrument system 200 includes a catheter system 202 coupled to aninstrument body 204. The catheter system 202 includes an elongatedflexible catheter body 216 having a proximal end 217 and a distal end ortip portion 218. In one embodiment, the flexible body 216 has anapproximately 3 mm outer diameter. Other flexible body outer diametersmay be larger or smaller. The entire length of the body 216, between thedistal end 218 and the proximal end 217, may be effectively divided intothe segments 224.

The catheter system 202 may optionally include a shape sensor 222 fordetermining the position, orientation, speed, velocity, pose, and/orshape of the catheter tip at distal end 218 and/or of one or moresegments 224 along the body 216. The shape sensor 222 may include anoptical fiber aligned with the flexible catheter body 216 (e.g.,provided within an interior channel (not shown) or mounted externally).In one embodiment, the optical fiber has a diameter of approximately 200μm. In other embodiments, the dimensions may be larger or smaller. Theoptical fiber of the shape sensor system 222 forms a fiber optic bendsensor for determining the shape of the catheter system 202.

The medical instrument system may optionally include a position sensorsystem 220. The position sensor system 220 may be a component of an EMsensor system with the sensor 220 including one or more conductive coilsthat may be subjected to an externally generated electromagnetic field.

The flexible catheter body 216 includes one or more working channelssized and shaped to receive an auxiliary instrument 226. Auxiliaryinstruments may include, for example, image capture probes, biopsyinstruments, laser ablation fibers, or other surgical, diagnostic, ortherapeutic tools. Auxiliary tools may include end effectors having asingle working member such as a scalpel, a blunt blade, an opticalfiber, or an electrode. Other end effectors may include, for example,forceps, graspers, scissors, or clip appliers. Examples of electricallyactivated end effectors include electrosurgical electrodes, transducers,sensors, and the like. In various embodiments, the auxiliary tool 226may be an image capture probe, such as an endoscope, that includes adistal portion with a stereoscopic or monoscopic camera at or near thedistal end 218 of the flexible catheter body 216 for capturing images(including video images) that are processed by the image capture system108 for display. The image capture probe may include a cable coupled tothe camera for transmitting the captured image data. Alternatively, theimage capture instrument may be a fiber-optic bundle, such as afiberscope, that couples to the visualization system. The image captureinstrument may be single or multi-spectral, for example capturing imagedata in one or more of the visible, infrared, or ultraviolet spectrums.

The auxiliary instrument 226 may house cables, linkages, or otheractuation controls (not shown) that extend between the proximal anddistal ends of the instrument to controllably bend the distal end of theinstrument. Steerable instruments are described in detail in U.S. Pat.No. 7,316,681 (filed on Oct. 4, 2005) (disclosing “Articulated SurgicalInstrument for Performing Minimally Invasive Surgery with EnhancedDexterity and Sensitivity”) and U.S. patent application Ser. No.12/286,644 (filed Sep. 30, 2008) (disclosing “Passive Preload andCapstan Drive for Surgical Instruments”), which are incorporated byreference herein in their entireties.

The flexible catheter body 216 may also houses cables, linkages, orother steering controls (not shown) that extend between the housing 204and the distal end 218 to controllably bend the distal end 218 as shown,for example, by the broken dashed line depictions 219 of the distal end.Steerable catheters are described in detail in U.S. patent applicationSer. No. 13/274,208 (filed Oct. 14, 2011) (disclosing “Catheter withRemovable Vision Probe”), which is incorporated by reference herein inits entirety. In embodiments in which the instrument system 200 isactuated by a teleoperational assembly, the housing 204 may includedrive inputs that removably couple to and receive power from motorizeddrive elements of the teleoperational assembly. In embodiments in whichthe instrument system 200 is manually operated, the housing 204 mayinclude gripping features, manual actuators, or other components formanually controlling the motion of the instrument system. The cathetersystem may be steerable or, alternatively, the system may benon-steerable with no integrated mechanism for operator control of theinstrument bending. Also or alternatively, one or more lumens, throughwhich medical instruments can be deployed and used at a target surgicallocation, are defined in the walls of the flexible body 216.

In various embodiments, the medical instrument system 200 may include aflexible bronchial instrument, such as a bronchoscope or bronchialcatheter, for use in examination, diagnosis, biopsy, or treatment of alung. The system 200 is also suited for navigation and treatment ofother tissues, via natural or surgically created connected passageways,in any of a variety of anatomical systems, including the colon, theintestines, the kidneys, the brain, the heart, the circulatory system,and the like. In various embodiments, the medical instrument may includea rigid construction (e.g. a rigid endoscope) rather than a flexiblecatheter.

In the embodiment of FIG. 2, the instrument 200 is teleoperated withinthe teleoperational medical system 100. In an alternative embodiment,the teleoperational assembly 102 may be replaced by direct operatorcontrol. In the direct operation alternative, various handles andoperator interfaces may be included for hand-held operation of theinstrument. FIG. 3 is a front view of the front of an endoscopicvisualization system, according to one example of principles describedherein.

To operate properly, the distal end of instrument 200 or other catheterinstruments, bronchoscopes, or endoscopes should remain free ofobstructions. The accumulation of patient fluids (e.g., mucous orblood), tissue, or cautery smoke on the lens of the imaging system or atthe opening of a catheter working channel may create an obstacle to thesafe and time efficient conduct of procedures using such instruments.Some cleaning methods involve injecting a fluid (e.g., gas or saline)through a nozzle aimed at the lens or removing the instrument from thepatient and wiping the distal end free of contaminants. Both of theseprocedures cost time which can affect both patient safety and costeffectiveness. The use of an injected fluid to clean the distal end ofthe instrument may raise concerns in certain situations; e.g., when theinstrument is inserted into a patient lumen (e.g., an airway passage ofthe lungs) and the outside diameter of the instrument tip completely orsubstantially fills the inside diameter of the patient lumen, sealingoff the anatomical region distal of the instrument tip. Excessive fluidinjected to clean the instrument tip may cause the sealed off portion ofthe anatomical region to overinflate and rupture the surrounding tissue.For example, if the instrument is a bronchoscope in use in a lung, suchexcess fluid injection into the region of the lung isolated by theimpacted instrument may cause a rupturing of the lung wall or pleura,resulting in pneumothorax. According to methods and systems describedherein, a more effective cleaning method for an instrument distal endminimizes the fluid discharged into the patient anatomy while adequatelyremoving the obstructing material.

FIG. 3 is a front view 300 of an elongated medical instrument 301, suchas an endoscope, a bronchoscope, flexible catheter instrument 200, orrigid imaging instrument. According to the present example, the medicalinstrument 301 includes catheter 302 with a channel 303 through which anelongated imaging instrument 305 extends. The imaging instrument 305includes a lens 306. The lens 306 may have an obstruction 308 thereon.The obstruction 308 may include a cloudy substance or an object thatobstructs vision through the visualization system. For example, patienttissue or patient fluids, such as blood or mucus, may stick to thesurface of the lens 306 and cloud the surface of the lens 306. Theobstruction 308 on the lens 306 is visible in images received by theimaging instrument 305 and sent to the user. A nozzle 304 is configuredto spray a fluid 310 across the surface of the lens to clear the lens ofthe obstruction 308. The fluid may be, for example, saline, carbondioxide, or air. Note that nozzle 304 can be any structure for guidingfluid 310 to a desired output location/configuration.

FIG. 4 is a diagram showing an illustrative fluid delivery system 400which may be a component of the fluid management system 109. The fluiddelivery system 400 provides short bursts of high-pressure fluid 310from nozzle 304 to the lens 306 of the medical instrument 301 to delivera low volume of the fluid 310 into the patient anatomy. According to thepresent example, the system 400 includes a pressurized fluid supply 402,a shutoff valve 404, a pressure regulator 406, a high-speed valve 408,an optional timer 412 controlled by a trigger 410, a fluid supply lumenextending through the medical instrument 301, and the nozzle 304.Together the timer 412 and the trigger 410 may be considered to be avalve control mechanism.

The fluid supply 402 may be pressurized through standard means (e.g.,compressed within a chamber) and may be part of an existing pressurizedfluid delivery system in the standard suite of utilities available in asurgical environment. The fluid supply 402 may be connected to thesystem 400 through the shutoff valve 404 that controls the flow of thefluid 310. To monitor and maintain the pressurization of the fluid 310,a pressure regulator 406 may be used.

In some embodiments, the pressure of the fluid 310 may be regulated tobe discharged at a pressure of between approximately 50 and 300 psi. Insome examples, the pressure of the fluid may be greater than 50, 60, 75,100, 150 or even 300 psi. The pressure of the fluid supply 402 isgreater than a standard pressure supplied by an operating room wall. Thestandard pressure supply of pressurized fluid in an operating room isapproximately 50 psi. In some examples, a pressure augmenting mechanismis used to create the higher pressurized fluid supply 402. Such pressureaugmenting mechanisms may include a fluid compressor such as an aircompressor. In some examples, the pressure augmenting mechanism may be apressure amplifier (such as a Model HAA31-2.5 or 85291 manufactured byHaskel). In some examples, the pressure augmenting mechanism may be ahigh pressure bottled gas that is used in accordance with an appropriateregulator.

In some embodiments, the high-speed valve 408 may be a valve 408 capableof being opened for shorts periods of time (e.g. 0.5 milliseconds) ascontrolled by the trigger 410 and the timer 412. When the valve 408 isopened, the pressurized fluid 310 is allowed to flow into the fluidsupply lumen extending within the medical instrument 301 to the nozzle304. In one example, the high speed valve 408 is a solenoid valve. Inone example, the high speed valve 408 is a Model MHJ-10 series valvemanufactured by Festo. Such a valve is capable of handling pressurizedfluid with a pressure ranging between 90-130 psi. In one example, thehigh speed valve 408 is a pneumatic valve.

The valve can be configured to automatically deactivate the flow ofpressurized fluid after a predetermined time interval that may bedetermined by the timer. In some embodiments, the predetermined timeinterval can be such that the total amount of fluid expended is below athreshold level. The threshold level can be set to reduce the risk ofover-inflation of a patient anatomy. The threshold level can take intoaccount the location of the instrument within a patient anatomy. Insmaller cavities of the anatomy, it may be desirable to minimize thetotal amount of fluid expended, and thus the threshold level may berelatively low, such as 0.4 cubic centimeters (ccs). In some slightlylarger cavities, a greater threshold level, such as 2 ccs may be used.Larger cavities may have an even larger threshold. In some embodiments,the threshold level can be adjusted according to the location of theinstrument, either manually (e.g., by the user based on manipulation ofthe instrument or viewing of x-ray or imaging data) or automatically(e.g., based on the position of the instrument within the patientanatomy determined by surgical navigation technology or positionsensors).

The opening of the high speed valve 408 is controlled by the trigger410. The trigger 410 will cause the valve 408 to open for apredetermined interval to release a pulse of fluid through the fluidsupply lumen of the medical instrument 301 to the nozzle 304. Thetrigger 410 may be implemented as hardware, software, or a combinationof the two. For example, the trigger may be a switch incorporated intothe operator input system 106 or at another location within theteleoperational medical system 100 and actuatable by the clinician or anassistant via, for example, motion of the clinician's hand or foot, averbal command, an eye gaze command, or use of user controlled implementsuch as a mouse. For example, the trigger 410 may be a foot pedal. Thetrigger may, alternatively, be provided via a touchpad, finger button,mouse button, or touchscreen button at the operator input system 106.The opening command conveyed via the trigger 410 may be communicated tothe valve 408 via the control system 112. In one example, if a cliniciannotices that the image on the screen (e.g., display 110, FIG. 1) isclouded due to an obstruction, the clinician may manually press thetrigger 410.

Although operation of the trigger 410 may be initiated by the clinicianor an assistant in response to the visualization of debris on the lens306, the operation of the trigger may also or alternatively be initiatedbased upon the system's detection of an obstruction. For example, anoptical sensor located at the distal end of the catheter 302 may detectan obstruction. In another example, the control system 112 may monitorthe images received via the lens 306 and detect (e.g. through theFourier transform-based analysis) matter occluding the lens. Based uponthis detection, the control system 112 may initiate operation of thetrigger.

In some examples, a more sophisticated process may be used to analyzethe image from an imaging system of a medical instrument in order todetermine whether the lens is dirty. For example, the medical instrumentmay be within a region of the anatomy where there is less texture andtherefore less sharpness and contrast. Sharpness, contrast, and otherparameters of an image will be referred to as the clarity of an image.The function for automatically determining if the lens is dirty canfactor in the position of the instrument as well as the observed clarityof the image. If the instrument is within a region of the anatomy whereless sharpness and contrast is expected, then a threshold amount ofclarity can be raised. Thus, even if the image appears somewhat lessclear, this does not necessarily mean that the lens is dirty and anautomatic pulse of fluid will not be directed across the lens. But, inareas where higher sharpness and contrast is expected, the claritythreshold may be lowered. Thus, when the image appears less clear, it ismore likely that this will trigger an automatic pulse of fluid acrossthe lens.

In some examples, a current image can be compared with a recentlyobtained image to determine if the lens is clouded and should becleared. For example, in a region with less contrast, the current imagecan be compared to a recent image. If the current image is substantiallymore clouded than the recent image, and the medical instrument has notmade a significant change in position, then it can be determined thatthe lens is dirty, and should be cleared. Thus, a pulse of fluid willautomatically be triggered.

In some examples, occlusion of the image may be factored into thedetermination of whether a pulse should be used. For example, if aparticular percentage of the image is occluded, then a pulse can beinitiated. In one example, a 20% occlusion may trigger the pulse offluid.

In some examples, a pulse of fluid may be automatically triggered at aspecific time interval. For example, a pulse of fluid may be directedacross the surface of the lens every 1, 2, or 5 seconds. Other timeintervals are contemplated as well. In this example, the user does nothave to be concerned with cleaning the lens. Rather, the cleaning of thelens is done automatically for the user and on average, the imageremains clearer than without the interval based pulses of fluid.

The closing of the high-speed valve 408 can be controlled by the timer412. The timer 412 may be set for a predetermined interval. The timer412 is initiated when the high-speed valve 408 is opened. The timer isset for the predetermined interval. When the predetermined period oftime has elapsed, the timer 412 causes the valve 408 to close. Forexample, the timer may send a signal to the valve instructing the valveto close. The timer may be incorporated into the control system 112 suchthat the control system sends signals to the valve. In one example, thepredetermined period of time may be selected from within a range ofapproximately 0.5 and 50 milliseconds. In various other embodiments, theperformance characteristics of system 400 can be selected or configuredto provide a desired fluid pulse time interval without the need for adedicated timer.

In some examples, the system 400 includes a shunt valve 409 to directany leakage from the high speed valve 408 away from the catheter passage303 leading to the nozzle 304. Thus, if there were to be any leakage inthe high speed valve 408, this additional fluid would pass through theshunt valve 409 and be directed somewhere else besides the interior ofthe patient's anatomy. The shunt valve 409 may also be controlled by thetrigger 412. Specifically, when the high speed valve 408 is opened todeliver fluid through channel 303 of catheter 302 to nozzle 304, theshunt valve 409 is switched from directing leakage fluid to a drainageline to the OFF or closed condition blocking loss of pressurized fluidfrom channel 303. In this mode, the valve command to shunt valve 409 isthe opposite of the command to fluid delivery valve 408 although inanother embodiment there may be overlap in the ON and OFF state timingof the valves. In some examples, a flow sensor can be used to determineif there is a leak in the high speed valve 408 when the valve should bein an OFF position, indicating that fluid should not be flowing at thattime. The shunt valve can then be used to direct any leaking fluid awayfrom the patient's anatomy.

In some examples, the pulse of fluid may be a gas. In some cases, thepulse of fluid may be a liquid such as a saline solution. In someexamples, pulses of fluid may alternate between a gas and a liquid. Thismay be done, for example, by using a valve to alternate between apressurized gas supply and a pressurized liquid supply. In someexamples, the final pulse in a series of alternating pulses may be apulse of gas.

In one example of a conventional fluid delivery system that does notinclude components such as the pressure regulator, the high-speed valve,the timer, or the trigger, fluid may be supplied at 10 psi forapproximately 0.10 seconds, as controlled by the operator, to deliverapproximately 10 cc's of fluid through the nozzle, across the lens, andinto the patient anatomy.

In one example using the fluid delivery system 400, fluid may besupplied at a higher pressure for a shorter duration to deliver asmaller volume of fluid. For example, at a pressure of 100 psi for aduration of 0.001 seconds controlled by the timer 412, the amount offluid discharged is approximately 0.316 cubic centimeters (cc). Comparedto the conventional system, the system 400 thus may discharge only 3.2%(a 31× reduction) of the fluid but at 10 times (1000% of) the pressure.The greater pressure provides a greater force for dislodgingobstructions from the lens and the distal tip of the catheter. Theamount of fluid discharged is lower, thus reducing the risk ofoverinflating the anatomy of the patient sealed off by the catheter.This reduces the risk of tissue perforation or other injury to thepatient. The reduced fluid volume may also reduce the drying effect of asustained air or carbon dioxide jet that can worsen adhesion of lenscontaminants. While the reduced volume of fluid expended is beneficialin smaller areas of the anatomy, the principles described herein may beapplied to situations where a medical instrument is within a largercavity of a patient anatomy.

In general, where the fluid is flowing (e.g. a gas or a liquid), thedynamic pressure can be defined as DP=(½) ρv². DP is the dynamicpressure; p is the fluid density; and v is the velocity. Thus, thedynamic pressure is dependent upon the velocity squared. The ability toremove an obstruction from a lens depends on the drag force F that afluid jet exerts on the obstruction. The drag force may be expressed asF=C_(d)×A×½ ρv², where C_(d) is a drag coefficient of the obstructionand A is a cross-sectional area of the obstruction normal to the flow.Thus the force on the obstruction depends on the square of the fluidvelocity. This means that a longer pulse with less pressure will producesubstantially more volume and with less force against obstructions onthe surface of the lens. Thus, by increasing the pressure and reducingthe pulse width, the lens can be more effectively cleared while using asmaller volume of fluid.

For example, using the equation described above, a 12 fold increase inpressure corresponds to approximately a 3.5 fold increase in velocity.Specifically, using the following equations, P1=% ρv₁ ² is increased 12times to P2=½ρv₂ ². This equation reduces to 12×v₁ ²=v₂ ², which furtherreduces to v₂=3.5 v₁. Thus, the volume flow rate for a fluid beingapplied across the surface of the lens increases approximately 3.5 foldwith a pressure increase of 12 fold. But, a substantial reduction intime expending fluid will result in a substantially smaller volume offluid being applied. For example, changing the width of the pulse fromabout 0.1 seconds to 0.001 s will result in a 100 fold drop in volume.Combined with the increased pressure, a higher velocity pulse exerting12× force on the obstruction and having about only 3.5% of the volumecan be achieved.

In some embodiments, a high pressure pulse of fluid may be provided by aspecific type of pump. For example, some types of pumps that may be usedinclude, but are not limited to, voice coil motor pumps, piezoelectricactuated pumps, servo motor controlled pumps, and solenoid actuatedpumps. Such pumps may be used in place of the high speed valve 408, thusallowing very short fluid pulses. In some cases, instead of using atimer, the pumps are configured to create a pulse with the appropriatewidth in response to a trigger.

FIG. 5A is a front view 500 of another embodiment of a medicalinstrument having a nozzle 508 for providing fluid to a surface of alens 502. According to this example, the nozzle 508 is positionedadjacent to one side of the lens 502. Illumination fibers 504 are alsoplaced near the lens to light up the interior of the passageways throughwhich the catheter 506 will navigate.

FIG. 5B provides a cross-sectional view of the medical instrument ofFIG. 5A. The nozzle 508 is positioned close to the surface of the lens502. A small opening 512 in the nozzle 508 is positioned and oriented toproject fluid parallel and close to the surface of the lens 502. Thenozzle 508 may connect to a port 514 that connects to a supply lumen.The fluid delivery system 400 may be used with the nozzle configurationof FIGS. 5A and 5B.

FIG. 6 is a perspective view 600 of a rounded or curved slot 604 forproviding fluid to a surface of a lens 502 of a medical instrument.According to this example, the nozzle 604 comprises a curved slot 604between the probe tip 602 and a catheter end piece 604 secured withinthe catheter jacket 608. With the curved slot 604, the fluid may bedelivered through a space between two inner lumens. For example, thefluid may be delivered between the fiber optic cable running through thecatheter, and a lumen that circumscribes the fiber optic cable. Thefluid may thus be projected from opening 604 at the top of face 602 andcentered at 606 across the lens 502 towards the opposite side of thelens exiting at the bottom of face 602. The fluid delivery system 400may be used with the nozzle configuration of FIG. 6. This medicalinstrument is described in greater detail in U.S. Patent Application No.[ISRG006000], which is incorporated by reference herein in its entirety.

FIG. 7 is a graph showing a pulse signal to cause a pulse of fluid to beapplied to a lens of a medical instrument. According to the presentexample, the horizontal axis 704 represents time. The vertical axis 702represents valve position. Specifically, the valve may be in a closedposition 710 or an open position 712. When the valve trigger isinitiated, a pulse signal is sent to the valve that opens admitting thepressurized fluid into the supply lumen. The timer is configured toprovide a pulse signal 706. The pulse width 708 (i.e., a duration) maybe set depending on the desired period of time for applying pressurizedfluid to the lens. As described above, the pulse width may range fromabout 0.5 milliseconds to 50.0 milliseconds. Other ranges for the pulsewidth are contemplated as well. Generally, the pulse width will be setbased on the pressure of the pressurized fluid. As described previously,in some embodiments a higher fluid pressure may permit adisproportionate decrease in pulse duration that provides increasedcleaning efficiency while greatly decreasing the volume of fluiddelivered.

In some examples, an open loop electric current waveform may be appliedto a valve or pump that is used to provide a pulse of fluid. The openloop waveform may be shaped to account for the system dynamics so thatthe pulse of fluid is applied as desired. For example, the waveform maybe shaped such that a pulse has an initial step but then drops slowly.Other types of pulse shapes may be used to cause the fluid pulse tobehave as desired. In some cases, however, a closed loop waveform may beused. Thus, a feedback control system can be used to carefully controlthe opening of a valve or movement of a pump to direct the desiredamount of fluid across the surface of the lens. For example, a feedbackcontrol loop can be used to control a pump to produce a pulse of fluidthat is less than two cubic centimeters.

FIGS. 8A and 8B are diagrams illustrating obstructions on the surface ofa lens. In some cases, the surface of the lens may be coated with ahydrophobic coating. FIG. 8A illustrates such a case. A hydrophobiccoating reduces the degree to which liquid substances adhere to thesurface of the lens 802. A liquid substance on the hydrophobic lenssurface 802 may be more likely to form round beads 804 as illustrated inFIG. 8A. This creates a higher drag coefficient Cd for the bead ofliquid 804 and places the center of the beaded obstruction 804 higher inthe flow 806 where the velocity is greater away from the surface of lens802. This also creates more surface area for the drag force.Specifically, the larger surface area corresponds to A and the higherdrag coefficient corresponds to the C_(d) in the equation describedabove, F=C_(d)×A×½ ρv². Thus, the force on the liquid droplet isincreased due to increases in the drag coefficient, the cross sectionalarea and the height of the projection into the flow of the fluid pulseapplied. Specifically, a pressurized fluid 806 being projected parallelto the surface 802 will catch more of the beaded obstruction 804 andmore effectively move or dislodge the obstruction 804. Additionally, thevelocity profile of fluid from the nozzle is such that the velocity isreduced at locations closer to the surface to which the liquid dropletis adhered due to the boundary layer, as will be appreciated by oneskilled in the art.

FIG. 8B illustrates a hydrophilic surface 803. With a hydrophilicsurface, a liquid obstruction 808 adheres firmly and more closely to thesurface 803. Thus the drag coefficient and the height of obstruction 808are reduced. Thus, the portion of pressurized fluid 806 impacting theadhered obstruction 808 will be at a lower velocity and exert a lowerforce on the more tightly adhered obstruction 808 and will lesseffectively remove the obstruction. Thus, removing obstructions from thesurface of the lens is made more efficient by applying a hydrophobiccoating 802 to the surface of the lens. Specifically, a hydrophobiccoating has the synergetic beneficial effect of increasing drag forceswhile reducing adhesion forces when used in conjunction with a jetdirected close and parallel to a lens surface and at higher velocitiesfor shorter durations.

FIG. 9 is a flowchart showing an illustrative method for clearing thelens of a medical instrument system. According to the present example,the method 900 includes a process 902 for controlling the pressure of apressurized fluid to a predetermined level or range. A process 904includes activating the flow of the pressurized fluid through a catheterof the medical instrument. A process 906 includes deactivating the flowof the pressurized fluid after a predetermined duration of time. Aprocess 908 includes directing the pressurized fluid across the distalsurface of the catheter. The process may be repeated until the lens ofan imaging system in the catheter is cleared of obstruction asdetermined by a user or by the detection systems described above. Insome alternative embodiments, a preset number of pulses may be deliveredeach time an obstruction is detected or pulses may be delivered at fixedintervals on a continuing basis.

The systems and methods of this disclosure may be used for connectedbronchial passageways of the lung. The systems and methods may also besuited for navigation and treatment of other tissues, via natural orsurgically created connected passageways, in any of a variety ofanatomical systems including the abdomen, colon, the intestines, thekidneys, the brain, the heart, the circulatory system, or the like. Themethods and embodiments of this disclosure are also suitable fornon-surgical applications.

The systems and methods described herein use the example where thesurface being cleared by the high pressure, short pulse of fluid is asurface of a lens of an imaging system. In some cases, however,principles described herein may be applied to other surfaces ofinstruments that can benefit from cleaning. For example, a pulse ofpressurized fluid may be applied to clear the surface of a lightdelivery tool, the tissue-contacting surface(s) of a surgical tool(e.g., the jaws of a grasper or vessel sealer, the blade of a scalpel,or the sampling structure of a biopsy tool).

One or more elements in embodiments of the invention may be implementedin software to execute on a processor of a computer system such ascontrol processing system 600. When implemented in software, theelements of the embodiments of the invention are essentially the codesegments to perform the necessary tasks. The program or code segmentscan be stored in a processor readable storage medium or device that mayhave been downloaded by way of a computer data signal embodied in acarrier wave over a transmission medium or a communication link. Theprocessor readable storage device may include any medium that can storeinformation including an optical medium, semiconductor medium, andmagnetic medium. Processor readable storage device examples include anelectronic circuit; a semiconductor device, a semiconductor memorydevice, a read only memory (ROM), a flash memory, an erasableprogrammable read only memory (EPROM); a floppy diskette, a CD-ROM, anoptical disk, a hard disk, or other storage device, The code segmentsmay be downloaded via computer networks such as the Internet, Intranet,etc.

Note that the processes and displays presented may not inherently berelated to any particular computer or other apparatus. Variousgeneral-purpose systems may be used with programs in accordance with theteachings herein, or it may prove convenient to construct a morespecialized apparatus to perform the operations described. The requiredstructure for a variety of these systems will appear as elements in theclaims. In addition, the embodiments of the invention are not describedwith reference to any particular programming language. It will beappreciated that a variety of programming languages may be used toimplement the teachings of the invention as described herein.

While certain exemplary embodiments of the invention have been describedand shown in the accompanying drawings, it is to be understood that suchembodiments are merely illustrative of and not restrictive on the broadinvention, and that the embodiments of the invention not be limited tothe specific constructions and arrangements shown and described, sincevarious other modifications may occur to those ordinarily skilled in theart.

1-48. (canceled)
 49. A method comprising: based on a position of amedical instrument within a patient anatomy, determining, by a controlsystem, whether an obstruction is on a surface of a lens of the medicalinstrument; and based on a determination that the obstruction is on thesurface of the lens, instructing, by the control system, a valve controlmechanism to open a valve to release a flow of pressurized fluid througha nozzle of the medical instrument and over the surface of the lens,wherein the valve is configured to control provision of the pressurizedfluid.
 50. The method of claim 49, wherein determining whether anobstruction is on the surface of the lens includes: receiving an imagefrom an imaging system of the medical instrument; and comparing aclarity of the received image to a threshold clarity.
 51. The method ofclaim 50, wherein the determination that the obstruction is on thesurface of the lens comprises a determination that the clarity of thereceived image does not satisfy the threshold clarity.
 52. The method ofclaim 50, wherein when the medical instrument is positioned in a firstregion of the patient anatomy, the threshold clarity is a firstthreshold clarity, and wherein when the medical instrument is positionedin a second region of the patient anatomy, the threshold clarity is asecond threshold clarity different from the first threshold clarity. 53.The method of claim 52, wherein the first region includes a region withless contrast than the second region, and wherein the first thresholdclarity is greater than the second threshold clarity.
 54. The method ofclaim 52, wherein the first region includes a region with highercontrast than the second region, and wherein the second thresholdclarity is greater than the first threshold clarity.
 55. The method ofclaim 49, further comprising: receiving, by the control system, a firstimage from an imaging system of the medical instrument; receiving, bythe control system, a second image from the imaging system of themedical instrument; and comparing, by the control system, a clarity ofthe first image to a clarity of the second image.
 56. The method ofclaim 55, wherein the determination that the obstruction is on thesurface of the lens comprises a determination that the clarity of thefirst image exceeds the clarity of the second image.
 57. The method ofclaim 49, wherein the pressurized fluid includes at least one of a gasor a liquid.
 58. The method of claim 49, wherein the flow of thepressurized fluid alternates between a flow of a gas and a flow of aliquid.
 59. The method of claim 49, wherein the pressurized fluidincludes at least one of air, carbon dioxide, or saline.
 60. A methodcomprising: detecting, by a control system, an obstruction on a surfaceof a lens of a medical instrument; and based on detecting theobstruction, instructing, by the control system, a valve controlmechanism to open a valve to release a flow of pressurized fluid from apressure augmenting mechanism, through a nozzle of the medicalinstrument, and over the surface of the lens, wherein an amount of theflow of the pressurized fluid is determined based on a position of themedical instrument in a patient anatomy, wherein the pressure augmentingmechanism is configured to provide the pressurized fluid at a pressurethat is higher than a standard operating room pressure, wherein thevalve is between the pressure augmenting mechanism and the nozzle, andwherein the valve is configured to control provision of the pressurizedfluid.
 61. The method of claim 60, wherein detecting the obstructionincludes detecting, by an optical sensor of the medical instrument, theobstruction.
 62. The method of claim 60, further comprising: receiving,by the control system, an image from an imaging system of the medicalinstrument; and determining, by the control system, an occlusion amountof the image.
 63. The method of claim 62, wherein detecting theobstruction includes determining that the occlusion amount exceeds athreshold occlusion amount.
 64. The method of claim 60, whereindetecting the obstruction includes determining, based on the position ofthe medical instrument within the patient anatomy, whether theobstruction is on the surface of the lens.
 65. The method of claim 60,wherein detecting the obstruction includes determining, based on theposition of the medical instrument within the patient anatomy, whetherthe obstruction is on the surface of the lens by: receiving an imagefrom an imaging system of the medical instrument; and comparing aclarity of the received image to a threshold clarity.
 66. The method ofclaim 65, wherein determining that the obstruction is on the surface ofthe lens comprises determining that the clarity of the received imagedoes not satisfy the threshold clarity.
 67. The method of claim 65,wherein when the medical instrument is positioned in a first region ofthe patient anatomy, the threshold clarity is a first threshold clarity,and wherein when the medical instrument is positioned in a second regionof the patient anatomy, the threshold clarity is a second thresholdclarity different from the first threshold clarity.
 68. The method ofclaim 60, wherein the pressurized fluid includes at least one of air,carbon dioxide, or saline.